Question

Why does my Segment warehouse sync show 0 rows synced even when the sync is marked as successful?

Product

Twilio Segment

Environment

Segment Console

Answer

A successful warehouse sync might show 0 rows synced if no data was found during the sync run. This typically happens for the following technical reasons:

• No New Data Found: Warehouses only sync new data or updates that have arrived since the last successful sync. If no new events were generated in that specific source during the sync window, the sync will successfully complete with 0 rows.

• Warehouse Selective Sync: Specific sources, collections, or properties might be disabled in the Selective Sync settings. When disabled, Segment stops sending new data to that schema, while other connected sources continue to sync normally.

• Schema Controls: Events might be blocked at the source level. If an event is toggled off in the Schema tab of your source, Segment permanently discards it before it reaches the pipeline, preventing it from reaching the warehouse.

• Data Deduplication: Segment evaluates the messageId to prevent duplicates. If the source sent data that were exact duplicates of events already synced within the last 24 hours, Segment drops them, resulting in 0 new rows synced.

To ensure data is flowing as expected, perform the following troubleshooting checks:

• Verify data arrival in Segment: Navigate to Connections > Sources, select your critical source, and open the Debugger tab. This real-time tool will confirm if API calls from your application or website are actually reaching your Segment source. If no data appears here, the issue lies upstream within the instrumentation.

• Review Selective Sync configuration: Navigate to Connections > Destinations, select your data warehouse, and open the Settings tab. Verify your Selective Sync configuration to ensure the critical source and the required collections are enabled.

• Review Schema Controls: Go to your critical source and open the Schema tab. Ensure that your important events do not have the block toggle activated.